Two Australian songwriters are suing Ed Sheeran and American country superstars Faith Hill and Tim McGraw over a "blatantly copied" song.

The Rest of Our Life, a song released by McGraw and Hill and co-written by Ed Sheeran, is the subject of a lawsuit from Australian songwriters Sean Carey and Beau Golden.

The suit, filed in New York federal court, claims the McGraw/Hill song "blatantly copied" their 2014 song When I Found You, which was performed by Jasmine Rae. The news was first reported by The Hollywood Reporter.

"The copying is, in many instances, verbatim, note-for-note copying of original elements of the song, and is obvious to the ordinary observer," the complaint reads.

Carey and Golden are represented by attorney Richard Busch, who won the pivotal Blurred Lines case that saw Marvin Gaye's family win a victory over Robin Thicke and Pharrell Williams over similarities between that song and Gaye's Got To Give It Up.

Busch was also behind a lawsuit against Sheeran over the song Photograph. That case was settled, with the songwriters being added to the credits.

Sheeran's co-writers, Johnny McDaid, Steve Mac and Amy Wadge, are also named in the suit along with several publishers, which seeks $5 million in damages along with an injunction for it to be permanently blocked.

The Blurred Lines decision has had a profound effect on the music industry, as evidenced by a current copyright dispute between Radiohead and Lana Del Rey over similarities between their song Creep.